California High School Exit Examination - Number sense solved Exercises 1-3 - Oct. 2008

From  California High School Exit Examination 2008

NUMBER SENSE

Exercise 1

1. The radius of the earth’s orbit is 150,000,000,000 meters. What is this number in scientific notation?

Solution 1

Answer A is not true because 150,000,000,000 is bigger than 1 and 1.5(ex-11) is little than 1.
In Scientific notation we use one digit before the point so answer B is true.


Exercise 2

Solution 2

We move the point two steps to the right and get:






Exercise 3
Which expression represents 0.0000007 in scientific notation?

Solution 3

The expression is little than 1 so the right answer is A or B.

We count how many steps we move the point left hand to get 0.0000007 from 7. The answer is 7 steps. The right answer B: 0.0000007 = 7(ex -7)